-
Korean Journal of Anesthesiology Jun 2019Randomized controlled trial is widely accepted as the best design for evaluating the efficacy of a new treatment because of the advantages of randomization (random... (Review)
Review
Randomized controlled trial is widely accepted as the best design for evaluating the efficacy of a new treatment because of the advantages of randomization (random allocation). Randomization eliminates accidental bias, including selection bias, and provides a base for allowing the use of probability theory. Despite its importance, randomization has not been properly understood. This article introduces the different randomization methods with examples: simple randomization; block randomization; adaptive randomization, including minimization; and response-adaptive randomization. Ethics related to randomization are also discussed. The study is helpful in understanding the basic concepts of randomization and how to use R software.
Topics: Bias; Humans; Random Allocation; Randomized Controlled Trials as Topic; Research Design; Selection Bias
PubMed: 30929415
DOI: 10.4097/kja.19049 -
European Journal of Epidemiology May 2017Mendelian randomization-Egger (MR-Egger) is an analysis method for Mendelian randomization using summarized genetic data. MR-Egger consists of three parts: (1) a test...
Mendelian randomization-Egger (MR-Egger) is an analysis method for Mendelian randomization using summarized genetic data. MR-Egger consists of three parts: (1) a test for directional pleiotropy, (2) a test for a causal effect, and (3) an estimate of the causal effect. While conventional analysis methods for Mendelian randomization assume that all genetic variants satisfy the instrumental variable assumptions, the MR-Egger method is able to assess whether genetic variants have pleiotropic effects on the outcome that differ on average from zero (directional pleiotropy), as well as to provide a consistent estimate of the causal effect, under a weaker assumption-the InSIDE (INstrument Strength Independent of Direct Effect) assumption. In this paper, we provide a critical assessment of the MR-Egger method with regard to its implementation and interpretation. While the MR-Egger method is a worthwhile sensitivity analysis for detecting violations of the instrumental variable assumptions, there are several reasons why causal estimates from the MR-Egger method may be biased and have inflated Type 1 error rates in practice, including violations of the InSIDE assumption and the influence of outlying variants. The issues raised in this paper have potentially serious consequences for causal inferences from the MR-Egger approach. We give examples of scenarios in which the estimates from conventional Mendelian randomization methods and MR-Egger differ, and discuss how to interpret findings in such cases.
Topics: Data Interpretation, Statistical; Genetic Pleiotropy; Genetic Variation; Humans; Mendelian Randomization Analysis; Models, Biological; Random Allocation; Risk Factors
PubMed: 28527048
DOI: 10.1007/s10654-017-0255-x -
Indian Journal of Dental Research :... 2017The effectiveness of ProTaper Universal and ProTaper Retreatment rotary instruments was compared to the Hedström files in the removal of filling material from root...
INTRODUCTION
The effectiveness of ProTaper Universal and ProTaper Retreatment rotary instruments was compared to the Hedström files in the removal of filling material from root canals.
MATERIALS AND METHODS
Thirty-six extracted human mandibular premolars with a single straight root canal were shaped and filled with gutta-percha and AH Plus. The specimens were stored for 6 months at 37°C and at 100% relative humidity, and then randomly divided into three groups: PTU - removal of filling material performed with ProTaper Universal instruments; PTR - removal of filling material performed with ProTaper Retreatment instruments; HF - removal of filling material performed with Gates-Glidden burs, Hedström files and solvent. After the filling material removal and diaphanization, the specimens were longitudinally sectioned and images of the canal surfaces were scanned. The remaining areas of filling material were measured (Image Tool 3.0), and data was analyzed statistically (Kruskal-Wallis and Dunn tests). The time required for filling removal in each group was also recorded (one-way ANOVA and Tukey's HSD test).
RESULTS
All groups presented remnants of filling material; PTU had the smallest amount and HF group presented the highest mean value (P< 0.05) in all the thirds. The cervical third had the smallest amount of material when compared with the other thirds (P< 0.05). HF group required a longer mean time, presenting significant difference (P< 0.05).
CONCLUSION
Considering the time required and the amount of the filling removal, ProTaper Retreatment were not superior to ProTaper Universal, but both rotary instruments were more effective and less time-consuming than Hedström manual files.
Topics: Bicuspid; Humans; In Vitro Techniques; Random Allocation; Retreatment; Root Canal Filling Materials; Root Canal Preparation; Treatment Outcome
PubMed: 28836531
DOI: 10.4103/ijdr.IJDR_89_16 -
International Journal of Epidemiology Nov 2021The causal nature of the observed associations between serum lipids and apolipoproteins and kidney function are unclear.
BACKGROUND
The causal nature of the observed associations between serum lipids and apolipoproteins and kidney function are unclear.
METHODS
Using two-sample and multivariable Mendelian randomization (MR), we examined the causal effects of serum lipids and apolipoproteins on kidney function, indicated by the glomerular-filtration rate estimated using creatinine (eGFRcrea) or cystatin C (eGFRcys) and the urinary albumin-to-creatinine ratio (UACR). We obtained lipid- and apolipoprotein-associated genetic variants from the Global Lipids Genetics Consortium (n = 331 368) and UK Biobank (n = 441 016), respectively, and kidney-function markers from the Trøndelag Health Study (HUNT; n = 69 736) and UK Biobank (n = 464 207). The reverse causal direction was examined using variants associated with kidney-function markers selected from recent genome-wide association studies.
RESULTS
There were no strong associations between genetically predicted lipid and apolipoprotein levels with kidney-function markers. Some, but inconsistent, evidence suggested a weak association of higher genetically predicted atherogenic lipid levels [indicated by low-density lipoprotein cholesterol (LDL-C), triglycerides and apolipoprotein B] with increased eGFR and UACR. For high-density lipoprotein cholesterol (HDL-C), results differed between eGFRcrea and eGFRcys, but neither analysis suggested substantial effects. We found no clear evidence of a reverse causal effect of eGFR on lipid or apolipoprotein traits, but higher UACR was associated with higher LDL-C, triglyceride and apolipoprotein B levels.
CONCLUSION
Our MR estimates suggest that serum lipid and apolipoprotein levels do not cause substantial changes in kidney function. A possible weak effect of higher atherogenic lipids on increased eGFR and UACR warrants further investigation. Processes leading to higher UACR may lead to more atherogenic lipid levels.
Topics: Apolipoproteins; Genome-Wide Association Study; Humans; Kidney; Lipids; Mendelian Randomization Analysis; Random Allocation; Triglycerides
PubMed: 34151951
DOI: 10.1093/ije/dyab014 -
Journal of Orthopaedic Surgery and... Jun 2018To analyze the safety and effects of early initiation of rehabilitation including objective measurement outcomes after lumbar spine fusion based on principles of... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
To analyze the safety and effects of early initiation of rehabilitation including objective measurement outcomes after lumbar spine fusion based on principles of strength training.
METHODS
The study recruited 27 patients, aged 45 to 70 years, who had undergone lumbar spine fusion. The method of concealed random allocation without blocking was used to form two groups. The strength training group started rehabilitation 3 weeks after surgery. Patients exercised twice weekly over 9 weeks focusing on muscle activation of lumbopelvic stabilization muscles. The control group followed a standard postoperative protocol, where no exercises were performed at that stage of rehabilitation. Functional outcomes and plain radiographs were evaluated at 3 weeks and subsequently at 3 and 18 months after the surgery.
RESULTS
No hardware loosening of failure was observed in the training group. Both groups improved their walking speed after 3 months (p < 0.01), although improvement in the training group was significantly greater than in the control group (p < 0.01). Moreover, the training group significantly improved after the training period in all isometric trunk muscles measurements (p < 0.03), standing reach height (p < 0.02), and pre-activation pattern (p < 0.05). After 18 months, no training effects were observed.
CONCLUSIONS
The study showed that early initiation of a postoperative rehabilitation program based on principles of strength training is safe, 3 weeks after lumbar spine fusion, and enable earlier functional recovery than standard rehabilitation protocol.
TRIAL REGISTRATION
The study is registered at the US National Institutes of Health ( ClinicalTrials.gov ) NCT03349580 . The date of registration: November 21, 2017 - Retrospectively registered.
Topics: Aged; Female; Humans; Lumbar Vertebrae; Male; Middle Aged; Muscle Strength; Random Allocation; Recovery of Function; Resistance Training; Spinal Diseases; Spinal Fusion; Time Factors; Torso; Treatment Outcome
PubMed: 29914580
DOI: 10.1186/s13018-018-0853-7 -
Circulation Research Jun 2016
Topics: Atherosclerosis; Endothelium, Vascular; Humans; Lipoproteins; Lipoproteins, HDL; Lipoproteins, LDL; Nitric Oxide; Random Allocation
PubMed: 27340266
DOI: 10.1161/CIRCRESAHA.116.309116 -
Tidsskrift For Den Norske Laegeforening... Oct 2018
Topics: Humans; Random Allocation
PubMed: 30378409
DOI: 10.4045/tidsskr.18.0555 -
Clinical Infectious Diseases : An... Aug 2021
Topics: Humans; Motivation; Random Allocation; Sample Size
PubMed: 32702084
DOI: 10.1093/cid/ciaa1027 -
The Journal of Thoracic and... Aug 2017
Topics: Feasibility Studies; Humans; Multiple Pulmonary Nodules; Random Allocation; Research Design
PubMed: 28412124
DOI: 10.1016/j.jtcvs.2017.03.069 -
Journal of Indian Prosthodontic Society Jan 2024
Topics: Random Allocation
PubMed: 38263552
DOI: 10.4103/jips.jips_545_23